Which filetypes can be explicitly searched for in Google search?

I was surprised not to find any data in the following google search

US Politics filetype:csv

After some tinkering, I realised any search for filetype:csv will return 0 results!

In the past, searches with filetype:csv would return results. There's nothing wrong with the operator itself, just the value, e.g. a search with filetype:pdf will return results.

What is the full list of acceptable values for filetype operator in Google search?

According to Google Advanced Search, the entire list is:

• Adobe Acrobat PDF (.pdf)
• Adobe Postscript (.ps)
• Autodesk DWF (.dwf)
• Google Earth KML (.kml)
• Google Earth KMZ (.kmz)
• Microsoft Excel (.xls)
• Microsoft Powerpoint (.ppt)
• Microsoft Word (.doc)
• Rich Text Format (.rtf)
• Shockwave Flash (.swf)